Is Infantile Hemangioma a Neuroendocrine Tumor?

Infantile hemangioma (IH) is the most common infantile tumor, affecting 5–10% of newborns. Propranolol, a nonselective β-adrenergic receptor (ADRB) antagonist, is currently the first-line treatment for severe IH; however, both its mechanism of action and its main cellular target remain poorly understood. Since betablockers can antagonize the effect of natural ADRB agonists, we postulated that the catecholamine produced in situ in IH may have a role in the propranolol response. By quantifying catecholamines in the IH tissues, we found a higher amount of noradrenaline (NA) in untreated proliferative IHs than in involuted IHs or propranolol-treated IHs. We further found that the first three enzymes of the catecholamine biosynthesis pathway are expressed by IH cells and that their levels are reduced in propranolol-treated tumors. To study the role of NA in the pathophysiology of IH and its response to propranolol, we performed an in vitro angiogenesis assay in which IH-derived endothelial cells, pericytes and/or telocytes were incorporated. The results showed that the total tube formation is sensitive to propranolol only when exogenous NA is added in the three-cell model. We conclude that the IH’s sensitivity to propranolol depends on crosstalk between the endothelial cells, pericytes and telocytes in the context of a high local amount of local NA.     

A combined computational fluid dynamics (CFD) and experimental approach to quantify the adhesion force of bacterial cells attached to a plane surface

A three‐dimensional model is developed to study the laminar shear flow past a bacterial cell attached to a plane surface. The induced hydrodynamic forces and torque exerted on the cell are computed to clarify the prevailing mechanisms involved in the detachment of model bacteria. Results are discussed in terms of drag and torque magnitude as a function of the angles defining the orientation of the cell. It is shown that reorientation and rolling of spheroid‐shaped cells are favored. It is also confirmed that rod‐shaped cells would tend to lie on the surface and become aligned with the flow. The model is used to quantify the adhesion force of spheroid Bacillus cereus spores to stainless steel, deduced from previously described experiments in a shear stress flow chamber. The magnitude of the predicted adhesion force is close to that obtained using atomic force microscopy under similar experimental conditions. © 2012 American Institute of Chemical Engineers AIChE J, 2012     

A macro- and micromechanics investigation of hot cracking in duplex steels

The relationship between microstructure and high temperature ductile tearing in duplex stainless steels has been investigated. Several grades were considered corresponding to different chemical compositions, different volume fractions and morphologies of the ferrite and austenite phases and different oxide inclusion contents. The high temperature cracking resistance has been quantified using both the essential work of fracture (EWF) and the fracture strain. The EWF discriminates the different grades of duplex steels and the different microstructures in terms of hot tearing resistance better than does the fracture strain. Metallographic characterization reveals that damage preferentially nucleates near inclusions at the austenite/ferrite boundary. Voids grow inside the ferrite until they coalesce. Damage develops more rapidly when increasing either the mismatch of rheology between the phases, which was evaluated by micro-scale strain measurements, or the inclusion content. The cracking resistance is related to the plastic work performed in the fracture process zone whereas the fracture strain depends on the damage kinetics. Both processes involve length scales related to the morphology and to the microstructure dimensions. Guidelines for improving the hot cracking resistance of duplex steels are formulated.     

Optical differential amplification in nonlinear fibre ring resonator

The theoretical basis and analytical expressions for the operation of a nonlinear fibre ring resonator as an optical differential amplifier are reported.<>     

GSR conditioning and personality factors in alcoholics and normals.

Alcoholic and nonalcoholic introversive and extroversive Ss were placed in a GSR conditioning situation. Significant differences in conditionability were not found between alcoholics and the nonalcoholic group with regard to the intro-extroversion dimension. The results were seen as confirming aspects of Eysenck's (1957) theory of personality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)